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Hard drives are still about 150MB/s.

SATA SSDs are limited to 550MB/s.

PCI-E 3.0 SSDs more like 3500 MB/s.

PCI-E 4.0 SSDs are 7000MB/s.

All of these are at consumer level pricing, you can get 2TB of PCI-E 4 from Western Digital for £130 at the moment, usually about £180. The issue is sustained writes more than reads for consumer verses enterprise drives where the speed drops off due to a lack of SLC caching and lack of cooling and TLC/QLC which is slower for sustained writing.

The example given is very much a consumer level device and not a particularly quick one by today's standards. You can also expect much faster reads cached than that on a DDR5 system I suspect.



It should be noted that those SSD speeds are all protocol limits rather than NAND flash limits. ~7GB/s is literally the maximum speed PCIE4 can provide, likewise ~3.5GB/s for PCIE3 and ~500MB/s for SATA3.


> the maximum speed PCIE4

4-lane PCIe, as most nvme drives are. I havent seen drives with wider lanes though...


Ah, right. Lanes. I should have mentioned those as well, thanks for catching that.


For me main difference between hdd and nvme is not really the throughput but the acces time. When you manipulate small files it's a lot more important


Todays large hard drives are over 250MBs in sequential operations




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